Abstract
The synthesis and structural characterisation (Fourier transform infrared, FTIR spectrometry, scanning electron microscopy, SEM and energy-dispersive X-ray, EDX) of amino-modified silicates (unloaded L1, and aspirin-loaded, L2) are reported. The optimal conditions for the extraction of aspirin from water by the modified silicate material were determined as a function of the mass of the extracting agent and the pH of the aqueous solution. The optimum mass was found to be 0.08-0.10 g with 99.9% removal of aspirin. Maximum extraction of aspirin by the material was observed at pH 4. The kinetics, the removal capacity of the material, as well as its recycling, were investigated. The results indicate that (i) the process is fast and (ii) the removal capacity for the drug is greater than that of previously reported materials and (iii)the modified silicate can be easily recycled. These data along with the low cost involved in the production of the material led to the conclusion that the modified silicate has the required potential for industrial use. Molecular simulation calculations suggest that one unit of aspirin interacts with one unit of the modified silicate L1 through hydrogen bond formation between the amine functional group of the silicate and the oxygen donor atoms of aspirin. Final conclusions are given.